X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-elf.c;h=3d6a9379f7a5e44b6837c01fbb5c72a92bd32162;hb=HEAD;hp=663699b7ce91a5d9febf0d9903b64d042a580782;hpb=3fbec7dc3645facd9e809cf161ba3435a377ce56;p=lttng-ust.git diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c deleted file mode 100644 index 663699b7..00000000 --- a/liblttng-ust/lttng-ust-elf.c +++ /dev/null @@ -1,687 +0,0 @@ -/* - * Copyright (C) 2015 Antoine Busque - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - -#define _GNU_SOURCE -#define _LGPL_SOURCE -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include "lttng-tracer-core.h" - -#define BUF_LEN 4096 - -/* - * Retrieve the nth (where n is the `index` argument) phdr (program - * header) from the given elf instance. - * - * A pointer to the phdr is returned on success, NULL on failure. - */ -static -struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, - uint16_t index) -{ - struct lttng_ust_elf_phdr *phdr = NULL; - off_t offset; - - if (!elf) { - goto error; - } - - if (index >= elf->ehdr->e_phnum) { - goto error; - } - - phdr = zmalloc(sizeof(struct lttng_ust_elf_phdr)); - if (!phdr) { - goto error; - } - - offset = (off_t) elf->ehdr->e_phoff - + (off_t) index * elf->ehdr->e_phentsize; - if (lseek(elf->fd, offset, SEEK_SET) < 0) { - goto error; - } - - if (is_elf_32_bit(elf)) { - Elf32_Phdr elf_phdr; - - if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) - < sizeof(elf_phdr)) { - goto error; - } - if (!is_elf_native_endian(elf)) { - bswap_phdr(elf_phdr); - } - copy_phdr(elf_phdr, *phdr); - } else { - Elf64_Phdr elf_phdr; - - if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) - < sizeof(elf_phdr)) { - goto error; - } - if (!is_elf_native_endian(elf)) { - bswap_phdr(elf_phdr); - } - copy_phdr(elf_phdr, *phdr); - } - - return phdr; - -error: - free(phdr); - return NULL; -} - -/* - * Retrieve the nth (where n is the `index` argument) shdr (section - * header) from the given elf instance. - * - * A pointer to the shdr is returned on success, NULL on failure. - */ -static -struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, - uint16_t index) -{ - struct lttng_ust_elf_shdr *shdr = NULL; - off_t offset; - - if (!elf) { - goto error; - } - - if (index >= elf->ehdr->e_shnum) { - goto error; - } - - shdr = zmalloc(sizeof(struct lttng_ust_elf_shdr)); - if (!shdr) { - goto error; - } - - offset = (off_t) elf->ehdr->e_shoff - + (off_t) index * elf->ehdr->e_shentsize; - if (lseek(elf->fd, offset, SEEK_SET) < 0) { - goto error; - } - - if (is_elf_32_bit(elf)) { - Elf32_Shdr elf_shdr; - - if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) - < sizeof(elf_shdr)) { - goto error; - } - if (!is_elf_native_endian(elf)) { - bswap_shdr(elf_shdr); - } - copy_shdr(elf_shdr, *shdr); - } else { - Elf64_Shdr elf_shdr; - - if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) - < sizeof(elf_shdr)) { - goto error; - } - if (!is_elf_native_endian(elf)) { - bswap_shdr(elf_shdr); - } - copy_shdr(elf_shdr, *shdr); - } - - return shdr; - -error: - free(shdr); - return NULL; -} - -/* - * Lookup a section's name from a given offset (usually from an shdr's - * sh_name value) in bytes relative to the beginning of the section - * names string table. - * - * If no name is found, NULL is returned. - */ -static -char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, off_t offset) -{ - char *name = NULL; - size_t len = 0, to_read; /* len does not include \0 */ - - if (!elf) { - goto error; - } - - if (offset >= elf->section_names_size) { - goto error; - } - - if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { - goto error; - } - - to_read = elf->section_names_size - offset; - - /* Find first \0 after or at current location, remember len. */ - for (;;) { - char buf[BUF_LEN]; - ssize_t read_len; - size_t i; - - if (!to_read) { - goto error; - } - read_len = lttng_ust_read(elf->fd, buf, - min_t(size_t, BUF_LEN, to_read)); - if (read_len <= 0) { - goto error; - } - for (i = 0; i < read_len; i++) { - if (buf[i] == '\0') { - len += i; - goto end; - } - } - len += read_len; - to_read -= read_len; - } -end: - name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */ - if (!name) { - goto error; - } - if (lseek(elf->fd, elf->section_names_offset + offset, - SEEK_SET) < 0) { - goto error; - } - if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) { - goto error; - } - - return name; - -error: - free(name); - return NULL; -} - -/* - * Create an instance of lttng_ust_elf for the ELF file located at - * `path`. - * - * Return a pointer to the instance on success, NULL on failure. - */ -struct lttng_ust_elf *lttng_ust_elf_create(const char *path) -{ - uint8_t e_ident[EI_NIDENT]; - struct lttng_ust_elf_shdr *section_names_shdr; - struct lttng_ust_elf *elf = NULL; - - elf = zmalloc(sizeof(struct lttng_ust_elf)); - if (!elf) { - goto error; - } - - elf->path = strdup(path); - if (!elf->path) { - goto error; - } - - elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC); - if (elf->fd < 0) { - goto error; - } - - if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) { - goto error; - } - elf->bitness = e_ident[EI_CLASS]; - elf->endianness = e_ident[EI_DATA]; - - if (lseek(elf->fd, 0, SEEK_SET) < 0) { - goto error; - } - - elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr)); - if (!elf->ehdr) { - goto error; - } - - if (is_elf_32_bit(elf)) { - Elf32_Ehdr elf_ehdr; - - if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) - < sizeof(elf_ehdr)) { - goto error; - } - if (!is_elf_native_endian(elf)) { - bswap_ehdr(elf_ehdr); - } - copy_ehdr(elf_ehdr, *(elf->ehdr)); - } else { - Elf64_Ehdr elf_ehdr; - - if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) - < sizeof(elf_ehdr)) { - goto error; - } - if (!is_elf_native_endian(elf)) { - bswap_ehdr(elf_ehdr); - } - copy_ehdr(elf_ehdr, *(elf->ehdr)); - } - - section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx); - if (!section_names_shdr) { - goto error; - } - - elf->section_names_offset = section_names_shdr->sh_offset; - elf->section_names_size = section_names_shdr->sh_size; - - free(section_names_shdr); - return elf; - -error: - if (elf) { - free(elf->ehdr); - if (elf->fd >= 0) { - if (close(elf->fd)) { - abort(); - } - } - free(elf->path); - free(elf); - } - return NULL; -} - -/* - * Test whether the ELF file is position independent code (PIC) - */ -uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf) -{ - /* - * PIC has and e_type value of ET_DYN, see ELF specification - * version 1.1 p. 1-3. - */ - return elf->ehdr->e_type == ET_DYN; -} - -/* - * Destroy the given lttng_ust_elf instance. - */ -void lttng_ust_elf_destroy(struct lttng_ust_elf *elf) -{ - if (!elf) { - return; - } - - free(elf->ehdr); - if (close(elf->fd)) { - abort(); - } - free(elf->path); - free(elf); -} - -/* - * Compute the total in-memory size of the ELF file, in bytes. - * - * Returns 0 if successful, -1 if not. On success, the memory size is - * returned through the out parameter `memsz`. - */ -int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz) -{ - uint16_t i; - uint64_t low_addr = UINT64_MAX, high_addr = 0; - - if (!elf || !memsz) { - goto error; - } - - for (i = 0; i < elf->ehdr->e_phnum; ++i) { - struct lttng_ust_elf_phdr *phdr; - - phdr = lttng_ust_elf_get_phdr(elf, i); - if (!phdr) { - goto error; - } - - /* - * Only PT_LOAD segments contribute to memsz. Skip - * other segments. - */ - if (phdr->p_type != PT_LOAD) { - goto next_loop; - } - - low_addr = min_t(uint64_t, low_addr, phdr->p_vaddr); - high_addr = max_t(uint64_t, high_addr, - phdr->p_vaddr + phdr->p_memsz); - next_loop: - free(phdr); - } - - if (high_addr < low_addr) { - /* No PT_LOAD segments or corrupted data. */ - goto error; - } - - *memsz = high_addr - low_addr; - return 0; -error: - return -1; -} - -/* - * Internal method used to try and get the build_id from a PT_NOTE - * segment ranging from `offset` to `segment_end`. - * - * If the function returns successfully, the out parameter `found` - * indicates whether the build id information was present in the - * segment or not. If `found` is not 0, the out parameters `build_id` - * and `length` will both have been set with the retrieved - * information. - * - * Returns 0 on success, -1 if an error occurred. - */ -static -int lttng_ust_elf_get_build_id_from_segment( - struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length, - off_t offset, off_t segment_end) -{ - uint8_t *_build_id = NULL; /* Silence old gcc warning. */ - size_t _length = 0; /* Silence old gcc warning. */ - - while (offset < segment_end) { - struct lttng_ust_elf_nhdr nhdr; - size_t read_len; - - /* Align start of note entry */ - offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN); - if (offset >= segment_end) { - break; - } - /* - * We seek manually because if the note isn't the - * build id the data following the header will not - * have been read. - */ - if (lseek(elf->fd, offset, SEEK_SET) < 0) { - goto error; - } - if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr)) - < sizeof(nhdr)) { - goto error; - } - - if (!is_elf_native_endian(elf)) { - nhdr.n_namesz = bswap_32(nhdr.n_namesz); - nhdr.n_descsz = bswap_32(nhdr.n_descsz); - nhdr.n_type = bswap_32(nhdr.n_type); - } - - offset += sizeof(nhdr) + nhdr.n_namesz; - /* Align start of desc entry */ - offset += offset_align(offset, ELF_NOTE_DESC_ALIGN); - - if (nhdr.n_type != NT_GNU_BUILD_ID) { - /* - * Ignore non build id notes but still - * increase the offset. - */ - offset += nhdr.n_descsz; - continue; - } - - _length = nhdr.n_descsz; - _build_id = zmalloc(sizeof(uint8_t) * _length); - if (!_build_id) { - goto error; - } - - if (lseek(elf->fd, offset, SEEK_SET) < 0) { - goto error; - } - read_len = sizeof(*_build_id) * _length; - if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) { - goto error; - } - - break; - } - - if (_build_id) { - *build_id = _build_id; - *length = _length; - } - - return 0; -error: - free(_build_id); - return -1; -} - -/* - * Retrieve a build ID (an array of bytes) from the corresponding - * section in the ELF file. The length of the build ID can be either - * 16 or 20 bytes depending on the method used to generate it, hence - * the length out parameter. - * - * If the function returns successfully, the out parameter `found` - * indicates whether the build id information was present in the ELF - * file or not. If `found` is not 0, the out parameters `build_id` and - * `length` will both have been set with the retrieved information. - * - * Returns 0 on success, -1 if an error occurred. - */ -int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id, - size_t *length, int *found) -{ - uint16_t i; - uint8_t *_build_id = NULL; /* Silence old gcc warning. */ - size_t _length = 0; /* Silence old gcc warning. */ - - if (!elf || !build_id || !length || !found) { - goto error; - } - - for (i = 0; i < elf->ehdr->e_phnum; ++i) { - off_t offset, segment_end; - struct lttng_ust_elf_phdr *phdr; - int ret = 0; - - phdr = lttng_ust_elf_get_phdr(elf, i); - if (!phdr) { - goto error; - } - - /* Build ID will be contained in a PT_NOTE segment. */ - if (phdr->p_type != PT_NOTE) { - goto next_loop; - } - - offset = phdr->p_offset; - segment_end = offset + phdr->p_filesz; - ret = lttng_ust_elf_get_build_id_from_segment( - elf, &_build_id, &_length, offset, segment_end); - next_loop: - free(phdr); - if (ret) { - goto error; - } - if (_build_id) { - break; - } - } - - if (_build_id) { - *build_id = _build_id; - *length = _length; - *found = 1; - } else { - *found = 0; - } - - return 0; -error: - free(_build_id); - return -1; -} - -/* - * Try to retrieve filename and CRC from given ELF section `shdr`. - * - * If the function returns successfully, the out parameter `found` - * indicates whether the debug link information was present in the ELF - * section or not. If `found` is not 0, the out parameters `filename` and - * `crc` will both have been set with the retrieved information. - * - * Returns 0 on success, -1 if an error occurred. - */ -int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf, - char **filename, uint32_t *crc, - struct lttng_ust_elf_shdr *shdr) -{ - char *_filename = NULL; /* Silence old gcc warning. */ - size_t filename_len; - char *section_name = NULL; - uint32_t _crc = 0; /* Silence old gcc warning. */ - - if (!elf || !filename || !crc || !shdr) { - goto error; - } - - /* - * The .gnu_debuglink section is of type SHT_PROGBITS, - * skip the other sections. - */ - if (shdr->sh_type != SHT_PROGBITS) { - goto end; - } - - section_name = lttng_ust_elf_get_section_name(elf, - shdr->sh_name); - if (!section_name) { - goto end; - } - if (strcmp(section_name, ".gnu_debuglink")) { - goto end; - } - - /* - * The length of the filename is the sh_size excluding the CRC - * which comes after it in the section. - */ - _filename = zmalloc(sizeof(char) * (shdr->sh_size - ELF_CRC_SIZE)); - if (!_filename) { - goto error; - } - if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) { - goto error; - } - filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE); - if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) { - goto error; - } - if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) { - goto error; - } - if (!is_elf_native_endian(elf)) { - _crc = bswap_32(_crc); - } - -end: - free(section_name); - if (_filename) { - *filename = _filename; - *crc = _crc; - } - - return 0; - -error: - free(_filename); - free(section_name); - return -1; -} - -/* - * Retrieve filename and CRC from ELF's .gnu_debuglink section, if any. - * - * If the function returns successfully, the out parameter `found` - * indicates whether the debug link information was present in the ELF - * file or not. If `found` is not 0, the out parameters `filename` and - * `crc` will both have been set with the retrieved information. - * - * Returns 0 on success, -1 if an error occurred. - */ -int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename, - uint32_t *crc, int *found) -{ - int ret; - uint16_t i; - char *_filename = NULL; /* Silence old gcc warning. */ - uint32_t _crc = 0; /* Silence old gcc warning. */ - - if (!elf || !filename || !crc || !found) { - goto error; - } - - for (i = 0; i < elf->ehdr->e_shnum; ++i) { - struct lttng_ust_elf_shdr *shdr = NULL; - - shdr = lttng_ust_elf_get_shdr(elf, i); - if (!shdr) { - goto error; - } - - ret = lttng_ust_elf_get_debug_link_from_section( - elf, &_filename, &_crc, shdr); - free(shdr); - - if (ret) { - goto error; - } - if (_filename) { - break; - } - } - - if (_filename) { - *filename = _filename; - *crc = _crc; - *found = 1; - } else { - *found = 0; - } - - return 0; - -error: - free(_filename); - return -1; -}